Is this new rental amendment acceptable?

We own a mobile home park (only 2 mobile home slots, actually), in Maine. We are closing the “park” in summer, for change of land use (we gave them a one-year notice, as required by law). We have been experiencing a water shortage (with the well running dry at times). Is it legally binding to send the tenants a 30-day amendment to the rental agreement (they are on month-to-month, not a lease) to offer water delivery services instead of trying to rely on the depleting and inconsistent well water? The only other thing we could do is to drill a new well. However, it would cost $6-7k and doesn’t make sense since the “park” will be closed permanently in a few months. (If we were keeping the park open, we would absolutely drill a new well.) The other issue is - the tenants aren’t paying their rent at all because of the water shortage problem. It appears they’re upset with us, even though we didn’t cause the problem. Any comments, suggestions, opinions, etc. would be helpful. (FYI: We also talked with a couple lawyers, but they haven't been much help and one was even incorrect with the laws. We pointed out two things in the law that he missed, and he said, "Well, you got me there.")